This disclosure relates generally to methods of making multiple-polymeric-layer thermoformed articles.
Thin plastic trays, sheets, liners, and other shaped articles have a wide variety of uses and functions.
Thin plastic trays are used for storage, shipping, and display of food items such as cookies (e.g., a three-trough tray for holding creme-filled sandwich cookies in rows of multiple cookies during shipping and sale), baked goods (e.g., a display box having a thin plastic insert that prevents shifting of and damage to delicate baked goods such as cupcakes or tarts during display and sale), and produce (e.g., an in-box separator that secures delicate fruits during shipping).
Thin shaped plastic articles are commonly used as disposable plates, cups, lids, and containers for holding, storing, protecting, or manipulating food and other items at the point of sale or consumption. Examples of such articles include plastic plates, beverage cup lids, salad bar trays and containers, clear lids for sealing foil food containers, and the like.
Disposable plastic liners, covers, and shields can also be used to provide a sanitary surface in environments in which soiling or contamination of a surface frequently occurs. In such environments, use of disposable plastic articles can significantly reduce the time and expense needed to maintain sanitation. By way of example, food service stations (e.g., buffet tables) have refillable food containers that typically must be cleaned or replaced prior to refilling with fresh food items. If the used surface of the container could be removed while leaving the container in place with a fresh, sanitary surface, delay and cost associated with cleaning or replacing the container could be avoided.
Disposable plastic liners and articles are also useful in situations in which the surface of an article becomes soiled and it is preferable, economically or aesthetically, to dispose of the soiled surface or article without cleaning it. By way of example, the surface of toilet seats, trash cans, and pet litter containers can harbor hazardous, malodorous, or distasteful substances and these substances can be difficult to remove safely and completely. If these articles were economically disposable or had removable liners which were conveniently and economically disposable, the difficulty of cleaning the articles and their surfaces can be avoided.
Use of disposable articles, trays, sheets, and liners in these and other circumstances is well known. Heretofore, significant difficulties have been experienced in making disposable articles and liners that can be economically and conveniently used. Machinery and operations for making individual liners, trays, inserts, and other thin shaped plastic articles are well known and frequently involve thermoforming plastic sheets to form articles having a shape adapted to fit the desired use. However, assembling, packaging, and installing multiple shaped plastic articles has been difficult and, in some instances, impossible. The very high tolerances required to stack or layer disposable plastic articles within one another and at their intended location of use is beyond the capacity of most processes for mass-producing the articles. As a result, many shaped plastic liners and other articles can only be installed one-at-a-time, rather than in a format permitting serial removal of individual articles from a multi-article bundle. Even for shaped articles for which nesting or stacking is not required or difficult, the economy of shaped plastic articles has been limited by the need to make individual shaped articles one at a time in, for example, a thermoforming mold.
There is a continuing need for a method of manufacturing a plurality of formed articles more efficiently and in a manner better adapted for providing multiple shaped articles in a nested conformation. The subject matter disclosed herein satisfies this need.